Magnifying attachment for slide rules



Patented June 18,1935

UNITED STATES PATENT OFFICE Henry P. White Plains, N. y.

Application January 5,

2 Claims.

My inventionrelates to improvements in magnifying attachments for slide rules.

The object of my invention is the provision of a lens which is siidably held to the surface I of the glass or transparent index portion of the rule by suction. The lens, which is of the plano convex type, is so designed that the flat or plane surface when moistened adheres to the glass index portion of the rule.

Standard slide rules are usually provided with upper and lower scale portions which are slidably adjustable with one another.

While I have illustrated and described my invention as applied to slide rules, it is readily apparent that my invention may be applied to any type of calculating machine or device employing calibrated scales.

My invention may be readily applied to such instruments or devices as automobile speedometers or similar instruments embodying calibrated scales which require quick or accurate readings.

In the present instance, I have illustrated and described my invention as applied to a standard form of slide rule or calculating device.

My invention is illustrated in the accompanyme drawing, wherein,

Figure 1 is a plan view showing the lens of my invention applied to the upper scale of a portion of a slide rule.

Fig. 2 is an end viewof Fig. 1.

Fig. 3 is a planview of the index portion of the slide rule showing the lens in pomtion with the lower scale.

Fig. 4 is a plan view of the lens.

Pig. 5 is a section of Fig. 4, on the. line 5-5.

Referring to Figs. 1 and 2, the bottom or base i of the slide rule is provided with grooves which are engaged by the tongues of the portions 4 and 'l, as plainly shown.

The slidable portion 4 is also plainly shown with a tongue which engages a groove in portion 3. The fixed portion 3 is provided with an additional groove which is engaged'by the tongue of portion 6. I

The'portions O and I serve tosupport the glass or index portion 8 which is held in position by the screws 9. The portions 3, I. are provided with calibrated scales 'as shown in Fig. 1. v r a The scales of portions 3 'and l, which are in adjustable relation to one another, constitute the upper scale; while the scales of portion 4, which are in adjustable relation to one another, constitute the-lower scale.

The index or t portion 8, which may 1933, Serial NO. 650384 be, of glass or other t material, has a pointer or line II which cooperates with the calibrations of the upper. and lower scales.

As plainly indicated in Fig. 1, the lens I0 when in the upper position as shown magnifies the calibrations of the upper scale so that the readings maybereadilymade. Whenthelens ll isinthe position shown in Fig. 3, the calibrations of the lower scale are readily ascertained.

In ordinary usages. the upper scale readings 10 may be read without the magnifying eflect, and insuchcasethelens ll isslidto thelowerposition, as in.Flg. 3. When the magnifying effect is not needed, when reading the lower scale, the

lens ll isslidtotheupperposition, asinl'ig. 1.

Whenever it is desiredto remove the lens II, it may be slid to the right or left, thus removing the adhering or suction eifect with the glass portion 8. r

As shownin Figs. 4 and 5, the lens I0 is of the plano convex type. In order to cause the lens to adhere to the index portion 8, the flat or plane surface ii is moistened and placed upon the surface of: the portion 8', and thereafter it may be slidably moved to any desired position. I

It is readily apparent that the lens l0 may be applied to automobile speedometers, voltmeters, ammeters, etc, in order to-magnify the scale to give a quick and. accurate reading when desired without the necessity of g-Loviding special attachments which interfere with standard types of instruments.

Having thus scribed my invention, what I desiretosean'cw r Pantim L The combination of a slide rule having an. giower scale. a graduated member slidable lnsitudinally between said scales, a flat t member having index line connecting the graduations onthe scales and on the graduated member, said t member be- 40 ing slidable longitudinally over the scales and over the graduated member, and a piano spherically convex lens slidably held to the t member by suction whereby it may be freely -mov'edthereon'n'omtheuppcrtothelowerscale.

2. The combination of a slide rule provided with an upper and a lower horizontally positioned scale, a graduated member slidable longitudinally between the scales, a flat transparent member movable along the slide rule and having an ind ex line for connecting the upper and lower scales and the graduations on the sliding member between the scales, a lens having its entire surface polished, said lens having a circular flat base 5 being such that the scales and the graduated member at or near the base of the lens is observable in magnified form along all radial lines extending therefrom.

HENRY P. CLAUSEN. 

